Device and method for stabilizing cold atom laser power

Abstract

The invention discloses a device and a method for stabilizing cold atom laser power, and belongs to the field of cold atoms. A device for stabilizing cold atom laser power comprises a laser generating unit, an acousto-optic modulator, an acousto-optic modulator driving module and a power stabilizing unit. Laser output by the laser generating unit is modulated by the acousto-optic modulator and then enters the power stabilizing unit, and the power stabilizing unit feeds back to the acousto-optic modulator driver to complete feedback of laser power so as to realize laser power stabilization. And the time sequence control unit issues an instruction to the state selection module through instruction control and controls the switching of the time sequence state in real time through triggering. The power stabilization unit further comprises an arbitrary function generation module, the arbitrary function generation module generates a function image of an arbitrary waveform to serve as a reference signal, the laser power is locked on the reference signal through the power stabilization unit, and arbitrary function image locking of the laser power is completed. The method has the advantages of high reliability, high stability, short locking time, easiness in operation and the like.

Description

Technical Field

[0001] The invention belongs to the field of cold atoms and relates to a device and a method for stabilizing the power of cold atom lasers. Background Art

[0002] In the field of cold atoms, fluctuations in optical power can affect measurement accuracy, which plays an important role in cold atom quantum simulation, computing, and precision measurement.

[0003] The current laser power locking used in the field of cold atoms usually uses analog circuits or digital circuits for locking. Most technologies use slow-loop feedback and the locking time is generally in the ms range, which makes it impossible to achieve μs-level locking during cold atom measurements. In addition, the laser power may have a ratio greater than 1:10 during the measurement cycle. It is difficult for the traditional single-loop power feedback loop to achieve such a large power change in a short time, and most of the purposes are to suppress long drift. In the field of cold atoms, the laser power changes continuously during the measurement process, and the real-time state locking of the laser is also one of the difficulties and hot spots. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for stabilizing the power of cold atom lasers, which can realize the feedback of laser power in the field of cold atoms to achieve laser power stability, and can suppress the influence caused by optical power jitter. The present invention has the advantages of strong reliability, high stability, short locking time, and easy operation.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The invention discloses a device for stabilizing the power of cold atomic lasers, comprising a laser generating unit, an acousto-optic modulator, an acousto-optic modulator driving module, and a power stabilizing unit. The laser output by the laser generating unit is modulated by the acousto-optic modulator and then enters the power stabilizing unit, which then feeds back to the acousto-optic modulator driver to complete the feedback of the laser power and realize the stabilization of the laser power.

[0007] The timing control unit sends instructions to the state selection module through instruction control to trigger the switching of the timing state in real time.

[0008] The power stabilization unit includes a photodiode, an AD acquisition module, a digital filter module, a timing control unit, a digital PID feedback module and a DA output module. The photodiode converts the optical signal into an electrical signal, which is collected by the AD acquisition module, and then passes through the digital filter module and the laser control timing module. The regulated laser enters the digital PID module, and the DA module outputs a signal to complete the control of the laser power.

[0009] The power stabilization unit also includes an arbitrary function generation module. The arbitrary function generation module generates a function image of an arbitrary waveform as a reference signal. The power stabilization unit locks the laser power on the reference signal, completes arbitrary function image locking of the laser power, and suppresses long-term jitter of the optical power.

[0010] The timing control unit is used to achieve short-time cold atom laser power stabilization and slow-loop PID feedback locking. The laser output by the laser generating unit enters the timing control module after being modulated by the acousto-optic modulator. The output laser passes through the photodiode, is collected by the AD acquisition module and fed back to the digital PID feedback module, and is output by the DA output module to the acousto-optic modulator driver to complete the laser power locking. After the conversion, different timing controls are used to complete the long-pulse laser power locking, and then the DA output module is fixed to output the DA value at the short pulse timing. The DA output is corrected in each cycle to complete the short-pulse laser power stabilization. In the acousto-optic modulator drive module, a mixer is used to replace the voltage-controlled attenuator. The mixer is a passive device that can solve the problem of slow response of active devices and can achieve us-level optical power stability.

[0011] The present invention discloses a method for stabilizing the power of a cold atom laser, which is implemented based on the device for stabilizing the power of a cold atom laser. The method for stabilizing the power of a cold atom laser is implemented as follows:

[0012] In the laser control timing, the initial state is in the first timing state. When receiving the command control, the state is reversed to the second timing state. Digital PID feedback is performed in different timing states, and different DA values ​​are output to complete the flipping of the laser timing.

[0013] In cold atom experiments, the laser power is not constant and often needs to be changed as a function. The present invention adds an arbitrary function generation module on the basis of timing reversal, completes the scanning of the laser power by scanning the acousto-optic modulator driver, and at this time completes the stabilization of the laser power by a power stabilization unit.

[0014] Beneficial effects:

[0015] 1. The present invention discloses a device and method for stabilizing the power of cold atom lasers, which adopts a working mode of multi-channel AD acquisition and multi-channel DA output to solve the problem of requiring one or more photodiodes to feedback a multi-channel acousto-optic modulator driver in different working states in the field of cold atom measurement. According to the measurement requirements, multi-channel AD acquisition and single-channel DA output or single-channel AD acquisition and multi-channel DA output and other modes are performed to meet the requirements of different laser powers at different stages such as cold atom measurement.

[0016] 2. In the cold atom measurement sequence, the laser power needs to be locked at different reference values. Using a set of PID parameters will lead to worsening of the locking noise. The present invention discloses a device and method for stabilizing the cold atom laser power. The device and method use the state flip function to lock the laser power using corresponding PID parameters in different states, and lock the laser power into a function image according to the sequence state. The present invention can significantly reduce the locking noise and improve the stability of the cold atom laser power stabilization device.

[0017] 3. The present invention discloses a device and method for stabilizing the power of cold atomic lasers. Different timing controls are used to complete the long pulse laser power locking and then fix the DA output module to output the DA value at the short pulse timing. The DA output is corrected in each cycle to complete the short pulse laser power stabilization. In the acousto-optic modulator drive module, a mixer is used to replace the voltage-controlled attenuator. The mixer is a passive device that can solve the problem of slow response of active devices and achieve us-level optical power stability.

[0018] 4. The present invention discloses a device and method for stabilizing the power of cold atomic lasers. The arbitrary function generation module generates a function image of an arbitrary waveform as a reference signal, and the power stabilization unit locks the laser power on the reference signal to complete the arbitrary function image locking of the laser power and suppress the long-term jitter of the optical power. The photodiode converts the optical signal into an electrical signal and is collected by the AD acquisition module. After the signal is collected by the digital filter module and the laser control timing module, the laser after regulation enters the digital PID module and the DA module outputs the signal to complete the control of the laser power, so that the present invention has better stability and higher sampling accuracy and calculation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 An example structural block diagram of a device for stabilizing the power of short-pulse cold atom lasers provided by the present invention;

[0020] Figure 2 An example structural block diagram of a laser power stabilization device provided by the present invention;

[0021] Figure 3 This is an example structural block diagram of a device for stabilizing laser power with multiple AD acquisition and multiple DA output provided by the present invention;

[0022] Figure 4 A structural block diagram of an example of a method for stabilizing short pulse laser power provided by the present invention;

[0023] Figure 5 A block diagram of the laser power state flip structure provided by the present invention;

[0024] Figure 6 The block diagram of the power locking structure of the laser power arbitrary function provided by the present invention;

[0025] In the figure: 10—laser generating unit, 20—acousto-optic modulator, 30—power stabilizing unit, 40—acousto-optic modulator driver, 31—photodiode, 32—AD acquisition, 33—digital filtering, 34—digital PID feedback control unit, 35—DA output, 100—laser power control timing, 101—command control, 102—state selection, 103—first timing state, 104—second timing state, 105—Nth timing state, 200—arbitrary function generating module. DETAILED DESCRIPTION

[0026] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0027] Embodiment 1:

[0028] like Figure 1 As shown, a method for stabilizing the power of cold atomic laser disclosed in this embodiment includes a laser generating unit 10, an acousto-optic modulator 20, an acousto-optic modulator driving module 40, and a power stabilization unit 30. The laser output by the laser generating unit 10 is modulated by the acousto-optic modulator 20 and then enters the power stabilization unit 30. The power stabilization unit feeds back to the acousto-optic modulator driver 40 to complete the feedback of the laser power and realize the stabilization of the laser power. The power stabilization unit is the size of two 3U boards of the standard VPX architecture.

[0029] The timing control unit 100 sends instructions to the state selection module 102 through the instruction control 101 to trigger the switching of the timing state in real time.

[0030] The power stabilization unit 30 also includes an arbitrary function generation module 200. The arbitrary function generation module 200 generates a function image of an arbitrary waveform as a reference signal. The power stabilization unit 30 locks the laser power on the reference signal, completes the arbitrary function image locking of the laser power, and suppresses the long-term jitter of the optical power. The locking speed is less than 10

[0031] μs, the optical power fluctuation is less than 0.8% in 15 hours.

[0032] The power stabilization unit 30 includes a photodiode 31, an AD acquisition module 32, a digital filter module 33, a timing control unit 100, a digital PID feedback module 34 and a DA output module 35. The photodiode 31 converts the optical signal into an electrical signal, which is collected by the AD acquisition module 32, and then controlled by the digital filter module 33 and the laser control timing module. The laser after regulation enters the digital PID module 34, and the DA module outputs a signal 35 to complete the control of the laser power.

[0033] The timing control unit 100 is used to achieve short-time cold atom laser power stabilization and slow-loop PID feedback locking. The laser output by the laser generating unit 10 is modulated by the acousto-optic modulator 20 and enters the timing control module. The output laser passes through the photodiode 31, is collected by the AD acquisition module 32 and fed back to the digital PID feedback module 34, and is output to the acousto-optic modulator driver 40 by the DA output module 35 to complete the locking of the laser power. After the conversion, different timing controls are used to complete the long-pulse laser power locking, and then the DA output module is fixed to fix the output DA value at the short pulse timing, and the DA output is corrected in each cycle to complete the short-pulse laser power stabilization. In the acousto-optic modulator driving module, a mixer is used to replace the voltage-controlled attenuator. The mixer is a passive device, which can solve the problem of slow response of active devices and can suppress the stability of 5us optical power.

[0034] The present embodiment discloses a method for stabilizing the power of a cold atom laser and an implementation method thereof:

[0035] The laser generating unit generates laser light, which is modulated by the acousto-optic modulator and then enters the timing control module. In the timing control 100, since the light pulse time is too short, a long pulse is added in the subsequent timing such as the second timing state 104, and the light signal is collected by the photodiode 31 to complete the conversion of the light signal to the electrical signal. The AD acquisition module 32 collects the electrical signal and passes through the digital PID module 34, calculates and records the DA output value after the laser power is stabilized, and in the next cycle, the DA output module 35 outputs the electrical signal recorded in the previous cycle, which is input to the acousto-optic modulator driver to complete the short pulse optical power locking, thereby suppressing the long-term jitter of the optical power. In the laser control timing 100, the initial state is in the first timing state 103. When the command control 101 is received, the state is reversed to the second timing state 104. Digital PID feedback 34 is performed in different timing states, and different DA values ​​are output to complete the flipping of the laser timing.

[0036] In cold atom experiments, the laser power is not constant and often needs to be changed as a function. The present invention adds an arbitrary function generation module 200 on the basis of timing inversion, and completes the scanning of the laser power by scanning the acousto-optic modulator driver. At this time, the laser power is stabilized by the power stabilization unit.

[0037] In cold atom experiments, the laser power is not constant and often needs to be changed as a function. The present invention adds an arbitrary function generation module 200 on the basis of timing inversion, and completes the scanning of the laser power by scanning the acousto-optic modulator driver. At this time, the laser power is stabilized by the power stabilization unit.

[0038] In the laser control timing, the initial state is in the first timing state. When receiving the command control, the state is reversed to the second timing state. Digital PID feedback is performed in different timing states, and different DA values ​​are output to complete the flipping of the laser timing.

[0039] In cold atom experiments, the laser power is not constant and often needs to be changed as a function. The present invention adds an arbitrary function generation module on the basis of timing inversion, and completes the scanning of the laser power by scanning the acousto-optic modulator driver. At this time, the laser power is stabilized by the power stabilization unit.

[0040] The above specific description further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for stabilizing the power of cold atom lasers, characterized in that: The invention comprises a laser generating unit (10), an acousto-optic modulator (20), an acousto-optic modulator driving module (40), and a power stabilizing unit (30); the laser output by the laser generating unit (10) is modulated by the acousto-optic modulator (20) and then enters the power stabilizing unit (30); the power stabilizing unit feeds back to the acousto-optic modulator driving module (40) to complete the feedback of the laser power and realize the stabilization of the laser power; The timing control unit (100) sends instructions to the state selection module (102) through the instruction control (101) to trigger the switching of the timing state in real time; The power stabilization unit (30) further comprises an arbitrary function generation module (200). The arbitrary function generation module (200) generates a function image of an arbitrary waveform as a reference signal. The power stabilization unit (30) locks the laser power on the reference signal, thereby completing arbitrary function image locking of the laser power and suppressing long-term jitter of the optical power.

2. A device for stabilizing cold atom laser power according to claim 1, characterized in that: The power stabilization unit (30) comprises a photodiode (31), an AD acquisition module (32), a digital filtering module (33), a timing control unit (100), a digital PID feedback module (34) and a DA output module (35); the photodiode (31) converts an optical signal into an electrical signal which is acquired by the AD acquisition module (32), and then passes through the digital filtering module (33) and is controlled by the laser control timing module. The regulated laser enters the digital PID feedback module (34) and the DA output module (35) completes the control of the laser power.

3. A device for stabilizing cold atom laser power according to claim 1, characterized in that: The timing control unit (100) is used to achieve short-time cold atom laser power stabilization and slow-loop PID feedback locking. The laser output by the laser generating unit 10 is modulated by an acousto-optic modulator (20) and then enters the timing control module; the output laser passes through a photodiode (31), is collected by an AD collection module (32) and fed back to a digital PID feedback module (34), and is output to an acousto-optic modulator driver (40) by a DA output module (35) to complete the locking of the laser power; after the conversion, different timing controls are adopted to complete the locking of the long-pulse laser power, and then the DA output module (35) is fixed to output a fixed DA value at the short-pulse timing, and the DA output is corrected in each cycle to complete the stabilization of the short-pulse laser power; in the acousto-optic modulator driver module (40), a mixer is adopted to replace a voltage-controlled attenuator, and the mixer is a passive device.

4. A method for stabilizing cold atom laser power, implemented according to the device for stabilizing cold atom laser power according to claim 1, 2 or 3, characterized in that: The implementation method is: In the timing control unit (100), the initial state is in the first timing state (103), and when receiving the instruction control (101), the state is reversed to the second timing state (104), digital PID feedback is performed in different timing states, and different DA values ​​are output to complete the flipping of the laser timing; In a cold atom experiment, the laser power undergoes a functional change, an arbitrary function generation module (200) is added on the basis of the timing flip, the laser power is scanned by a scanning acousto-optic modulator driver based on the arbitrary function generation module (200), and the laser power is stabilized by a power stabilization unit (30).

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